take this with a grain of salt, as there are many things that can make or break a track, and when a screener says "mix isn't competitive" then you have to ask yourself:
"is this just a great track cloaked in a bad mix"
or,
"is this not "broadcast Quality"" - which is a combination of the production, the elements, the melodies, the sounds, AND the mix.
When I listen to this track I hear more of the second thing - that the entire production doesn't sound totally pro. Keep in mind, that you will always get a better critique on your pieces in this peer to peer forum by pasting the ENITRE listing into your original post as well as the link to your track. Some listings only make sense when you consider the sound palette that is in the reference tracks.
If you want to know more about broadcast quality:
www.ustream.tv/recorded/31835637 and
www.ustream.tv/recorded/59198143 might help.
But some things to consider:
kick drum - sounds like its got a lot of snap (nail in the paddle) but little resonant low frequencies, where most hip hop tracks are still based on 808 style kicks (sometimes doubled with other sounds) which have a characteristic long resonant sound especially when compressed hard or distorted in parallel. With hip hop tracks that might be lacking in a bass instrument, the long resonant 808 sound makes up for the lack of bottom in the mix.
drum groove - sounds a little over quantized, or quantized straight instead of having a SLIGHT swing. It doesn't make me want to move.
Strings - while a lot of hip hop tracks exhibit some degree of quantization (especially the MPC 16 note or 8th note swings) these strings sound totally wooden and stiff.
electric guitar - this is a 50/50 thing. Sometimes you hear that in tracks. But its also something that can date a track. If the ref tracks for the listing your wrote this for have prominent 80's sounding distorted electrics, then go for it. If they don't, stay away from that sound.
mix - when everything drops out, and its just strings and drums, it sounds like the ambience that we had on the previous section totally disappeared. Sometimes that works. In this case, it caught me by surprise, and not necessarily a good kind of surprise.
HTH